In Haskell we write `f` in order to infixify the identifier f. In ABC
the stuff between backquotes is not limited to an identifier, but any
expression may occur there. This would allow one to write e.g.
xs `zipWith (+)` ys
In general <expr1> `<expr2>` <expr3> => (<expr2>) <expr1> <expr3>
I think it is a small extension to Haskell, which does not break
anything existing, and provides yet another opportunity to beautify
one programs, especially in combination with programs like lhs2TeX.
Doaitse Swierstra